The test of an effective problem play is whether the audience leaves the theater still processing the information. And the Manoa Valley Theatre production of "Doubt" passes that test with high marks.

After 90 minutes of dense exposition and character development, the central character — Sister Aloysius Beauvier — delivers the provocative curtain line with more emotion than she has revealed all evening.

"I have such doubts!" sends us into the parking lot still coming to grips with her meaning.

Excellently delivered by Jo Pruden — who's worn a nun's habit in previous productions, but never with more moral authority — Sister Aloysius is clearly harder than granite and colder than steel. She's the self-appointed guardian of a Catholic grammar school, feared by all, and just the person to put a little "starch in your character."

Clearly an old-school Catholic, she's personally convinced that the young pastor — who wants to bring fresh air into a stuffy institution — has developed an unhealthy interest in a friendless eighth-grade boy. Sister Aloysius begins a mission to "bring him down."

Are Sister Aloysius' suspicions the product of her paranoia? After all, she condemns "Frosty the Snowman" for its heretical images and bans the use of ballpoint pens because they destroy good penmanship. Does what she sees in the priest reveal a deeper truth, or is it a witch hunt fueled by twisted conclusions?

The play is set in the early 1960s, when the Church hadn't yet begun to consider the possibility of pedophilia among its clergy. Nuns and priests led rigidly segregated and structured lives, and "obedience" was a major calling.

So in several scenes without intermission, the play unravels itself, causing the audience to question all they see and hear and to ultimately doubt its own conclusions.

Pruden's performance correctly keeps her character at arm's length from the audience. We aren't meant to like Sister Aloysius, or even to fully understand her strict personal code.

We're more prone to like Russell Motter as the casual and disarming Father Flynn, who coaches basketball, hosts bull sessions for the boys over soft drinks and cookies, and befriends the only black kid in the school.

We can't help but like Melanie Garcia as young and enthusiastic Sister James, whose passion for teaching is squelched by Sister Aloysius' demands that she be vigilant in observing the students under her care.

And we puzzle over Anette Kauahikaua as the boy's mother, who reacts to Sister Aloysius' suspicions that the child may have been "interfered with" in a most unexpected way.

Vanita Rae Smith directs the small cast and elicits excellent personal and ensemble work. Willie Sabel's set design of stone, stained glass and wrought iron blends with MVT's concrete block walls and lighting grid to give the impression that the entire space is a single large church.

But the compelling part of the production is the answer to Sister Aloysius' last line. In what does she have latent doubt? In herself or in her church?

The follow-up discussions — in the parking lot and elsewhere — are well worth having.